Ebola

COLD STORAGE An Ebola vaccine tested in West Africa is stored at –80° C in a canister that researchers can take out into the field. More than 5,000 people in Guinea received the vaccine in a trial to gauge its efficacy.

Of 5,837 people in Guinea who received a single shot of the vaccine, rVSV-ZEBOV, in the shoulder, none became infected with the virus 10 to 84 days after vaccination. That’s “100% protection,” researchers report December 22 in the Lancet.

World Health Organization researcher Ana Maria Henao-Restrepo and colleagues tested a “ring vaccination” approach, by immediately vaccinating family members and other contacts of people infected with Ebola. This strategy seemed to staunch the virus’s spread. Among 4,507 people never vaccinated or who got a delayed vaccine, 23 contracted Ebola.

The findings echo preliminary results reported in 2015, and offer a promising line of defense for future outbreaks. But scientists still do not know how long-lasting the vaccine’s protection would be.